This flashing doesn’t look secure and likely damaged. It will need repair to prevent leaking.

Determining where the leak is penetrating…

Often times when water is leaking into a home there is confusion, even among professionals, as to where it is entering. Here at my company, we always treat water problems as a process of elimination starting with the least expensive repair first, which is generally waterproofing the chimney or repointing open mortar joints. If we pinpoint the leak to the flashing on the chimney, then chimney flashing repair becomes necessary.

What is flashing?

What is flashing? Water flows down the roof alongside the chimney at the flashing, making it a high traffic area for water. Leaks in the flashing are common because of this fact. They join together intersections between two planes, such as where the roof meets a chimney or skylight. Flashing is formed from sheet metal or plastic, and over time work itself loose from the roof, rust, or deteriorate. Even galvanized metal flashing has the possibility of deteriorating, and the older your home gets, the more likely you are to have problems with the flashing on your roof. A chimney flashing leak is not difficult to repair and quite common.

Okay! Let’s Repair!

When you go about with your flashing repair you need to decide how severe the damage is. If it is very minor, repairing it will be the route you want to take. Replacing your flashing all together is going to be the route that makes the repair last the longest however. There are many different kinds of flashing. Flashing around the places where pipes penetrate the roofline is called vent pipe flashing. Step flashing is used around dormer windows. This is the type of flashing used around the chimney and is named due to its appearance- it looks like stair steps.

Roof flashing is important because it prevents leaks. It works with gravity and the structure of it directs the water off of the roof so it doesn’t pool and cause leaks or the roof to sink in. Remember that the purpose of roof flashing is to keep water away from the wood underneath to prevent rotting.

Clay Lamb is a Cincinnati Chimney Sweep contractor and the executive producer of the YouTube channel, podcast, and blog Ask the Chimney Sweep. He is also an award-winning educator and public speaker in the chimney and fireplace industry.